The invention deals with separation of objects according to weight and, more particularly, to an improved method and apparatus for separating defective light weight pecans, hereinafter sometimes referred to as "pops," from heavier good pecans.
Typically, "pops" will be either shriveled-up or normal in appearance and hollow on the inside, and attempts have been made to remove such lighter, defective pecans from the heavier, good pecans by conveying them under an air vacuum nozzle and suctioning the lighter pecans from a foraminous or meshed conveyor. A problem experienced with these attempts, at various negative pressures which are sufficient for vacuuming at least one "pop" from the good pecans, is that a defective pecan restricts the suction nozzle, resulting in an increase in the suction felt by the remaining pecans on the conveyor and the removal of good, heavier pecans therefrom by this increased suction. In order to remove an acceptable amount of the "pops" by the prior art devices, a costly loss of good, heavier pecans is also experienced.
It is an object of this invention to provide a method and apparatus for separating objects, particularly pecans, according to weight by extracting the lighter objects from the heavier objects by vacuum while preventing the heavier objects from experiencing a vacuum increase which is sufficient to extract them along wih the lighter objects, wherein such an increased vacuum on the heavier objects is caused by restriction of a vacuum nozzle or duct.
It is a further object of the invention to limit the vacuum applied to the objects to be separated to a level which, in itself, is insufficient to draw-up the objects to a position of restriction of the vacuum nozzle, while providing a positive pressure to the other side of the objects which is sufficient to move the "lights" away from the "heavies", and wherein any unrestricting of the pressure nozzle outlet by removal of an object therefrom will result in reduced pressure on the remaining objects situated in front of the outlet nozzle.
Additionally, it is an object of the instant invention to regulate the negative pressure applied to an object by raising or lowering the suction nozzle in response to a restriction of the nozzle by any of the objects.